This research project is concerned with (i) the determinants of unemployment costs and risks among older workers; (ii) the determinants of older workers' behavioral adjustments to unemployment experiences; (iii) a comparison of determinants of unemployment and adjustment to it between older and younger workers; and (iv) variations in older workers' "success" in adjustments to unemployment, particularly with respect to their job-specific characteristics and their prior unemployment and wage histories. Framing our questions these ways necessitates construction of spell-specific and, separately, quarter-specific information from unique longitudinal disaggregated data on workers who ever experience unemployment, workers who experience none, and their employers through eight years of work and unemployment histories. In the first half of our research, unemployment spell patterns to be examined include the number, timing, spacing, and duration of spells; and the dependence of current unemployment characteristics on past unemployment characteristics. Second, we reclassify unemployment spells by their degree of permanence (reduced hours, temporary layoff, indefinite but nonpermanent layoff, and permanent layoff). Relating employer decisions to the older worker, we examine (i)-(iv) differentiating by whether a worker was employed in a contracting plant, in a contracting firm, in a declining industry; and, separately, in a plant which shut down either before or at the point of his separation to see how age is related to such complex risks. Determinants and comparisons of unemployment spell patterns are thirdly examined for age groups over the business cycles during the l975-82 period. In the second part of our research, unemployment adjustments examined include acceptance of recall, if it occurs, job change within the industry, job change outside the pre-spell industry, and exit from the workforce. The determinants of older workers' earnings changes and their subsequent unemployment instability following reemployment are then estimated to assess the effect of age on the above adjustments and choices, and the outcomes of such choices. A final measure of unemployment adjustment consists of retraining; analyses of demand and outcomes of retraining older workers are conducted to conclude our study of behavioral adjustments to the unemployment risks initially studied. Data from l975-82 will be updated with those from l983-85 as the research proceeds.